Wafer-level integrated opto-electronic module

ABSTRACT

A method to manufacture optoelectronic modules comprises a step of providing a first wafer comprising a plurality of first module portions, wherein each of the first module portions comprises at least one passive optical component, providing a second wafer comprising a plurality of second module portions, wherein each of the second module portions comprises at least one optoelectronic component. The wafers are disposed on each other to provide a wafer stack that is diced into individual optoelectronic modules respectively comprising one of the first and the second and the third module portions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to European ApplicationNo. 15178897.3, filed on Jul. 29, 2015, the content of which is reliedupon and incorporated herein by reference in its entirety.

FIELD

The disclosure is directed to a method to manufacture optoelectronicmodules. The disclosure is further directed to an optoelectronic module.

BACKGROUND

The capability to provide sub-micrometer to few micrometer opticalalignment accuracy has been a costly and time-consuming necessity inmost optical communication components and devices because of the smalldimensions of typical optical waveguides. As an example, in an activeoptical cable, PDs (Photodiodes) and multi-mode VCSELs (Vertical CavitySurface Emitting Lasers) are placed individually within about10-micrometer accuracy onto a populated PCB (Printed Circuit Board) withelectronic components. This populated PCB is then moved to a differentmachine for wirebonding and once again back to the precision placementmachine to place an optical element with lenses and a turning mirror.Fibers are brought onto the optical element on the PCB to complete thelink to the optoelectronic module.

If any failures occur in this process, such as damaging a VCSEL or poorplacement accuracy, the entire PCB is lost. This loss is expensive giventhe PCB must be pre-populated with all the electronics through the dirtysurface mount technology (SMT) process prior to the final clean opticalassembly described above. Additionally, each placement of PDs, VCSELsand a lens block has a tolerance of about 10 μm and thus creates a stackup allocation, i.e. the placement tolerances accumulate, for a largererror distribution in placement, which becomes especially problematic athigher data rates above 10 Gbps.

As a second example, silicon photonics structures use single modeoperation, which must couple into a single mode fiber with aperturestypically less than 10 μm. Consequently, alignment accuracies need to bewithin just a few micrometers, e.g. 2-1 μm, or better, to get reasonableoptical coupling. The use of pick and place tooling, while capable ofachieving these alignment accuracies, takes a significant amount of timeand thus increases cost of the overall system.

It is a desire to provide a method to manufacture optoelectronicmodules, wherein alignment tolerances between a respective optical fibercoupled to the optoelectronic modules, a respective at least one passiveoptical component and a respective at least one optoelectroniccomponents of the modules, are reduced and wherein a large amount of theoptoelectronic modules can be manufactured in a small amount of time. Afurther need is to provide an optoelectronic module, wherein alignmenttolerances between an optical fiber coupled to the optoelectronicmodule, at least one passive optical component and at least oneoptoelectronic component of the module are reduced and wherein theoptoelectronic module can be manufactured in a low time.

SUMMARY

According to an embodiment of a method to manufacture optoelectronicmodules, a first wafer comprising a plurality of first module portionsis provided, wherein each of the first module portions comprises atleast one passive optical component, wherein the at least one passiveoptical component has a first and a second side and is configured tomodify a beam of light such that a direction of light coupled in the atleast one passive optical component at the first side is changed andcoupled out of the at least one passive optical component at the secondside. Furthermore, a second wafer comprising a plurality of secondmodule portions is provided, wherein each of the second module portionscomprises at least one optoelectronic component and metalized via holesextending in a material of the second wafer from a first surface of thesecond wafer to a second opposite surface of the second wafer, andwherein the respective at least one optoelectronic component of thesecond module portions is electrically connected to the respectivemetalized via holes of the second module portions. A third wafercomprising a plurality of third module portions is provided, whereineach of the third module portions comprises at least one electroniccomponent.

The second wafer is bonded onto the third wafer such that the respectiveat least one electronic component of the third module portions iselectrically coupled to the respective at least one optoelectroniccomponent of the second module portions by means of the respectivemetalized via holes of the second module portions. Furthermore, thefirst wafer is bonded onto the second wafer to provide a wafer stacksuch that each of the first module portions is aligned to a respectiveone of the second module portions so that light coupled into therespective at least one passive optical component of the first moduleportions at the first side of the respective at least one passiveoptical component is coupled out at the second side of the respective atleast one optical component and is directed to the respective at leastone optoelectronic component of the second module portions.

The wafer stack is diced into individual optoelectronic modulesrespectively comprising one of the first and the second and the thirdmodule portions.

An embodiment of an optoelectronic module being manufactured by means ofthe method comprises a first substrate comprising a first module portionof the optoelectronic module including at least one passive opticalcomponent. The module comprises a second substrate comprising a secondmodule portion of the optoelectronic module including at least oneoptoelectronic component. Furthermore, the module comprises a thirdsubstrate comprising a third module portion of the optoelectronicmodule, wherein the third module portion comprises at least oneelectronic component.

The first substrate has a first surface and a second opposite surface,wherein the at least one optical component is arranged on the firstsurface of the first substrate. The at least one passive opticalcomponent has a first and a second side and is configured to modify abeam of light such that a direction of light coupled in the at least oneoptical component at the first side is changed and coupled out of the atleast one passive optical component at the second side.

The second substrate has a first surface and an opposite second surface,wherein the at least one optoelectronic component is arranged on thefirst surface of the second substrate. The second substrate comprisesmetalized via holes extending in a material of the second substrate fromthe first surface of the second substrate to the second surface of thesecond substrate. The at least one optoelectronic component iselectrically connected to the metalized via holes.

The second substrate is bonded onto the third substrate such that the atleast one electronic component of the third module portion iselectrically coupled to the at least one optoelectronic component of thesecond substrate by the metalized via holes of the second substrate. Thefirst substrate is bonded onto the second substrate such that the firstmodule portion is aligned to the second module portion so that lightcoupled into the respective at least one passive optical component ofthe first module portion at the first side of the at least one opticalcomponent is coupled out at the second side of the at least one opticalcomponent and is directed to the at least one optoelectronic componentof the second module portion.

The method allows to provide a plurality of optoelectronic modules,wherein the alignment tolerances between the respective at least oneoptoelectronic device, for example a photodiode, a laser or a siliconphotonics chip, and the respective at least one passive opticalcomponent, and an optical fiber coupled to the respective optoelectronicmodule are in a range of a few micrometers, for example in a range ofabout 1-2 μm. Thus, it is possible to reduce fallout, cost and time ofassembly of such modules and final PCBs. The method uses wafer-scalealignment and may further use wafer-scale testing while also making thefinal module SMT compatible.

The wafer-scale technique allows manufacturers to achieve the lowalignment tolerances across hundreds to thousands of devicessimultaneously, thus reducing overall cost and time. By also making itwafer-scale testable prior to assembly, fallout of the final assembleddevice on the PCB can be reduced. The modules may be designed to becompatible with typical semiconductor manufacturing processes, such asSMT, so that the optoelectronic module manufactured by theabove-specified method can be integrated into a final product withoutadded assembly cost. The method to manufacture the optoelectronicmodules can be used for active optical cables, silicon photonics andoptical fiber connections or potentially free-space connectivity acrossmany industries. Additionally, the manufacturing method would enable thelarge volume that may ensue due to the wafer-scale design, low cost andease of assembly. Lastly, the manufacturing tolerances provided couldlend itself to making a low-cost, robust module capable of speeds muchgreater than 10 Gbps and thus provide a path toward innovation requiringhigh data rate communication.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment of a method to manufacture optoelectronicmodules.

FIG. 2A shows several wafers to be stacked for manufacturing a pluralityof optoelectronic modules.

FIG. 2B shows an embodiment of stacked wafers for manufacturing aplurality of optoelectronic modules.

FIG. 3 shows an embodiment of optoelectronic modules of threesubstrates.

FIG. 4 shows a perspective view of a cutout of stacked wafers formanufacturing a plurality of optoelectronic modules.

FIG. 5 shows an embodiment of stacked wafers for manufacturing aplurality of optoelectronic modules.

FIG. 6 shows an embodiment of stacked wafers for manufacturing aplurality of optoelectronic modules.

FIG. 7 shows an embodiment of stacked wafers for manufacturing aplurality of optoelectronic modules.

FIG. 8A shows a perpendicular attachment of an embodiment of anoptoelectronic module onto an electronic board.

FIG. 8B shows a perpendicular attachment of an embodiment of anoptoelectronic module onto an electronic board.

FIG. 9A shows a downward attachment of an embodiment of anoptoelectronic module onto an electronic board.

FIG. 9B shows a downward attachment of an embodiment of anoptoelectronic module onto an electronic board.

FIG. 10A shows a vertical attachment of an embodiment of anoptoelectronic module onto an electronic board.

FIG. 10B shows a vertical attachment of an embodiment of anoptoelectronic module onto an electronic board.

FIG. 11A shows a downward attachment of an embodiment of anoptoelectronic module onto an opto-electronic board with an embeddedwaveguide.

FIG. 11B shows a downward attachment of an embodiment of anoptoelectronic module onto an opto-electronic board with an embeddedwaveguide.

FIG. 12A shows an embodiment of a downward arrangement of anoptoelectronic module onto an electronic board.

FIG. 12B shows an embodiment of a downward arrangement of anoptoelectronic module onto an electronic board.

FIG. 12C shows an embodiment of a downward arrangement of anoptoelectronic module onto an electronic board.

FIG. 13A shows an embodiment of several stacked wafers for manufacturinga plurality of optoelectronic modules.

FIG. 13B shows an embodiment of several stacked wafers for manufacturinga plurality of optoelectronic modules.

FIG. 14 shows an exploded view of several layers of an optoelectronicmodule.

FIG. 15A shows an embodiment of several substrates to be stacked aboveeach other for manufacturing an optoelectronic module.

FIG. 15B shows an embodiment of stacked substrates of an optoelectronicmodule.

FIG. 16A shows an embodiment of stacked substrates of an optoelectronicmodule.

FIG. 16B shows an embodiment of stacked substrates of an optoelectronicmodule.

FIG. 17A shows an embodiment of several substrates to be stacked aboveeach other for manufacturing an optoelectronic module.

FIG. 17B shows an embodiment of stacked substrates of an optoelectronicmodule.

FIG. 18A shows an embodiment of stacked substrates of an optoelectronicmodule.

FIG. 18B shows an embodiment of stacked substrates of an optoelectronicmodule.

FIG. 18C shows an embodiment of stacked substrates of an optoelectronicmodule.

FIG. 19 shows an embodiment of stacked substrates of an optoelectronicmodule.

DETAILED DESCRIPTION

The method to manufacture optoelectronic modules will now be describedin more detail hereinafter with reference to the accompanying drawingsshowing different embodiments of the method. The method may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that the disclosure will fully convey the scope of themethod to those skilled in the art. The drawings are not necessarilydrawn to scale but are configured to clearly illustrate the method. Thewritten text included in some of the Figures should facilitate theunderstanding of the Figures and particularly indicates examples ofmaterials which may be used for the different components, substrates andlayers but does not limit the possible materials that can be used forthese components, substrates and layers to the materials specified inthe Figures.

FIG. 1 shows steps A to F of a method to simultaneously manufacture aplurality of optoelectronic modules. The method is based on providing awafer stack of several wafers 100, 200 and 300, wherein each of thewafers comprises respective different components of the optoelectronicmodules. The wafer stack is diced into the individual optoelectronicmodules. FIG. 2A illustrates respective embodiments of a first wafer100, a second wafer 200 and a third wafer 300 to be stacked to eachother. FIG. 2B shows the wafer stack of the bonded first wafer 100, thesecond wafer 200 and the third wafer 300.

According to a step A of the method to manufacture the optoelectronicmodules, the first wafer 100 comprising a plurality of first moduleportions 101 is provided. Each of the first module portions 101comprises at least one passive optical component 110. The at least onepassive optical component 110 has a first and a second side and isconfigured to modify a beam of light such that a direction of the lightcoupled in the at least one passive optical component 110 at the firstside is changed and coupled out of the at least one passive opticalcomponent 110 at the second side.

At least one optical fiber can be aligned to the at least one passiveoptical component 110 so that light may be coupled from the at least oneoptical fiber into the at least one passive optical component 110 orcoupled out of the at least one passive optical component 110 into theat least one optical fiber. Optical fiber alignment components such asfixtures to hold and align an optical fiber can be mounted on the firstwafer 100. According to another embodiment, the fiber alignmentcomponents can be configured as wafers stacked on top of the first wafer100.

According to a subsequent step B, the second wafer 200 comprising aplurality of second module portions 201 is provided. Each of the secondmodule portions 201 comprises at least one optoelectronic component 210and metalized via holes 220 extending in a material of the second wafer200 from a first surface S200 a of the second wafer to a second oppositesurface S200 b of the second wafer. The respective at least oneoptoelectronic component 210 of the second module portions 201 iselectrically connected to the respective metalized via holes 220 of thesecond module portions 201.

According to a subsequent step C, the third wafer 300 comprising aplurality of third module portions 301 is provided. Each of the thirdmodule portions comprises at least one electronic component 310.

According to a subsequent step D, the second wafer 200 is bonded ontothe third wafer 300 such that the respective at least one electroniccomponent 310 of the third module portions 301 is electrically coupledto the respective at least one optoelectronic component 210 of thesecond module portions 201 by means of the respective metalized viaholes 220 of the second module portions 201.

According to a subsequent step E, the first wafer 100 is bonded onto thesecond wafer 200 to provide a wafer stack such that each of the firstmodule portions 101 is aligned to a respective one of the second moduleportions 201 so that light coupled into the respective at least onepassive optical component 110 of the first module portions 101 at thefirst side of the respective at least one passive optical component 110is coupled out at the second side of the respective at least one opticalcomponent 110 and is directed to the respective at least oneoptoelectronic component 210 of the second module portions 201.

According to a subsequent step F, the wafer stack comprising the firstwafer 100, the second wafer 200, and the third wafer 300 is diced intoindividual dies respectively comprising one of the first and the secondand the third module portions 101, 201 and 301 for respectively formingone of the optoelectronic modules. Each of the optoelectronic modules isformed by a respective first module portion 101 of the first wafer 100,a respective second module portion 201 of the second wafer 200 and arespective third module portion 301 of the third wafer 300, wherein therespective first, second and third module portions are stacked andbonded above each other.

The first wafer 100 is provided in the step A with a first surface S100a and a second surface S100 b being opposite to the first surface S100a. The respective at least one passive optical component 110 of each ofthe first module portions 101 is arranged on the first surface S100 a ofthe first wafer 100. The second wafer 200 is provided in step B with therespective at least one optoelectronic component 210 of each of thesecond module portions 200 being arranged on the first surface S200 a ofthe second wafer 200. According to an embodiment of method step C, thefirst wafer 100 is bonded onto the second wafer 200 such that the secondsurface S100 b of the first wafer 100 is disposed on the first surfaceS200 a of the second wafer 200.

FIG. 3 shows several optoelectronic modules 1 after being diced out ofthe wafer stack comprising the first wafer 100, the second wafer 200 andthe third wafer 300. Each of the optoelectronic modules 1 comprises afirst substrate 100′ being cut out of the first wafer 100 of the waferstack and comprising the first module portion 101 of the respectiveoptoelectronic module including the at least one passive opticalcomponent 110. Furthermore, each of the optoelectronic modules 1comprise a second substrate 200′ being cut out of the second wafer 200of the wafer stack and comprising the second module portion 201 of therespective optoelectronic module including the at least oneoptoelectronic component 210. Each of the optoelectronic modules furthercomprises a third substrate 300′ being cut out of the third wafer 300 ofthe wafer stack and comprising the third module portion 301 of theoptoelectronic module, wherein the third module portion 301 comprisesthe at least one electronic component 310.

The first substrate 100′ has a first surface and a second oppositesurface, wherein the at least one passive optical component 110 isarranged on the first surface of the first substrate 100. The at leastone passive optical component 110 has a first and a second side and isconfigured to modify a beam of light such that a direction of the lightcoupled in the at least one optical component 110 at the first side ischanged and coupled out of the at least one passive optical component110 at the second side.

The second substrate 200′ has a first surface and an opposite secondsurface, wherein the at least one optoelectronic component 210 isarranged on the first surface of the second substrate 200′. The secondsubstrate 200′ comprises the metalized via holes 220 extending in amaterial of the second substrate 200′ from the first surface of thesecond substrate to the second surface of the second substrate. The atleast one optoelectronic component 210 is electrically connected to themetalized via holes 220.

The second substrate 200′ is bonded onto the third substrate 300′ suchthat the at least one electronic component 310 of the third moduleportion 301 is electrically coupled to the at least one optoelectroniccomponent 210 of the second module portion 201 by the metalized viaholes 220 of the second substrate 200′. The first substrate 100′ isbonded onto the second substrate 200′ such that the first module portion101 is aligned to the second module portion 201 so that light coupledinto the respective at least one passive optical component 110 of thefirst module portion 101 at the first side of the at least one opticalcomponent is coupled out at the second side of the at least one opticalcomponent 110 and is directed to the at least one optoelectroniccomponent 210 of the second module portion 201.

According to an embodiment of the method to manufacture theoptoelectronic module, the second wafer 200 may be configured as a GaAsor a silicon photonics wafer or an InP wafer. The first wafer 100 may beconfigured as one of a glass wafer and an opaque polymer wafer withholes drilled out and filled with a transparent polymer. The respectiveat least one passive optical component 110 of the first module portions101 may comprise an optical lens and/or a light turning element, forexample an optical mirror, being configured to change a direction of thelight beam, for example by TIR (Total Internal Reflection), so thatlight is coupled between an optical fiber coupled to the respectivefirst module portions 101 and the respective at least one passiveoptical component 110 of the first module portions 101.

The respective at least one optoelectronic component 210 of the secondmodule portions 201 may be configured as an optical emitter, for examplea VCSEL, and/or an optical receiver, for example a photodiode. Therespective at least one electronic component 310 of the third moduleportions 301 may be configured as an electrical driver and/or anelectrical amplifier.

As explained above, the first opto-mechanical wafer 100 may comprises asubstrate of glass. Glass can provide a flat surface to mold opticalcomponents, such as lenses and turning mirrors, on the first wafer 100.Glass can also have precision features etched into its surface andthrough the first wafer 100 to allow for any mechanical alignment ofoptical fibers or other components. Furthermore, glass can be designedwith coefficients of thermal expansion (CTEs) similar to semiconductorwafers, thus improving reliability of the final optoelectronic modulesover large temperature ranges. Lastly, glass is an ideal substrate forhigh-speed signal integrity and both metal traces and vias can be madeon it.

FIG. 4 shows a perspective view of an embodiment of an optoelectronicmodule 1 after dicing the wafer-scale stack in perspective view, whereineach of the first, second and third module portions 101, 201 and 301comprises electrical contact pads to provide an external electricalconnection to the electrical and/or optoelectronic components of themodule or to electrically connect the electrical and optoelectroniccomponents to each other.

According to an embodiment of the method to manufacture theoptoelectronic modules, the second wafer 200 can be provided in methodstep B with respective electrical contact pads 230 for each of thesecond module portions 201. The respective electrical contact pads 210are electrically coupled to the respective metalized via holes 220 ofthe second module portions 201. The respective electrical contact pads230 are arranged on the second surface S200 b of the second wafer 200.

In method step C, the third wafer 300 is provided with respectiveelectrical contact pads 330 for each of the third module portions 301.The respective electrical contact pads 330 are electrically coupled withthe respective at least one electronic component 310 of the third moduleportions 301. The respective electrical contact pads 330 are arranged ona surface S300 a of the third wafer.

According to an embodiment of method step D, the second wafer 200 isbonded onto the third wafer 300 such that the second surface S200 b ofthe second wafer 200 is disposed on the surface S300 a of the thirdwafer 300 and the respective electrical contact pads 330 of the thirdmodule portions 301 are aligned to the respective electrical contactpads 230 of the second module portions 201 to provide an electricalconnection between the respective electrical contact pads 330 of thethird module portions 301 and the respective electrical contact pads 230of the second module portions 201.

According to an embodiment of the method to manufacture theoptoelectronic modules, the third wafer 300 is provided in method step Awith respective metalized via holes 320 for each of the third moduleportions 301 in a material of the third wafer 300. The respectivemetalized via holes 320 extend from the first surface S300 a of thethird wafer 300 to a second opposite surface S300 b of the third wafer300. The respective electrical contact pads 330 of the third moduleportions 301 arranged on the first surface S300 a of the third wafer 300are electrically coupled to the respective metalized via holes 320 ofthe third module portions 301.

The third wafer 300 is provided with respective electrical contact pads340 for each of the third module portions 301 on the second surface S300b of the third wafer 300. The respective electrical contact pads 340 ofthe third module portions 301 on the second surface S300 b areelectrically coupled to the respective metalized via holes 320 of thethird module portions 301. According to the embodiment of theoptoelectronic module 1 shown in FIG. 4, the optoelectronic modulecomprises the electrical contact pads 330 and 340 being arranged on bothsurfaces S300 a and S300 b of the wafer 300.

According to a further embodiment of the method to manufacture theoptoelectronic modules, the first wafer 100 is provided in method step Awith respective metalized via holes 120 for each of the first moduleportions 101 in a material of the first wafer 100. The respectivemetalized via holes 120 extend from the first surface S100 a of thefirst wafer 100 to the second surface S100 b of the first wafer 100.

According to an embodiment of the method step B, the second wafer 200 isprovided with respective electrical contact pads 240 for each of thesecond module portions 201 on the first surface S200 a of the secondwafer 200 such that the respective electrical contact pads 240 of thesecond module portions 201 are electrically connected to the respectivemetalized via holes 220 of the second module portions 201.

According to an embodiment of the method step E, the first wafer 100 isbonded onto the second wafer 200 such that the respective electricalcontact pads 240 of the second module portions 201 are electricallyconnected to the respective metalized via holes 120 of the first moduleportions 101.

According to another embodiment of the method to manufacture theoptoelectronic modules, the first wafer 100 is provided in method step Awith respective electrical contact pads 130 for each of the first moduleportions 101 on the second surface S100 b of the first wafer such thatthe respective electrical contact pads 130 of the first module portions101 are electrically connected to the respective metalized via holes 120of the first module portions 101.

Furthermore, the first wafer 100 can be provided in method step A with aconductive redistribution layer 150 on the second surface S100 b of thefirst wafer 100. The conductive redistribution layer 150 comprisesrespective conductive traces for each of the first module portions 101,wherein the respective conductive traces of the conductiveredistribution layer 150 are arranged to electrically couple therespective contact pads 130 of the first module portions 101 on thesecond surface S100 b of the first wafer 100 to the respective metalizedvia holes 120 of the first module portions 101.

According to the embodiment of the optoelectronic module 1 shown in FIG.4, the first module portion 101 comprises electrical contact pads 130arranged on the second surface S100 b of the wafer 100 and electricalcontact pads 140 arranged on the first surface S100 a of the first wafer100. The electrical contact pads 140 on the top surface S100 a of thefirst wafer 100 could allow for flip-chip bonding of the optoelectronicmodule 1.

According to an embodiment of the method to manufacture theoptoelectronic modules, the second wafer 200 comprising the secondmodule portions 201 with the respective optoelectronic components 210 isconfigured as a wafer made of GaAs. The electrical signals wouldtraverse from the top surface of the third wafer 300 comprising thethird module portions with the respective electronic components throughthe GaAs vias 220 of the second wafer 200 to the first wafer 100comprising opto-mechanical components 110 to connect the electricalsignals to an external electronic board, for example a PCB.

Additionally, the vias 220 would electrically connect the second wafer200 to the third wafer 300 containing either laser drivers or receiveramplifiers as electronic components to drive the optoelectroniccomponents, for example the VCSELs or PDs, of the second waferrespectively. In this implementation, the top first wafer 100 would havepassive optical components such as lenses and turning mirrors, as wellas opto-mechanical components for fiber attachment components and alsocomprises electrical traces and vias to connect to an external boardsuch as a PCB. In configuring the stack up using GaAs vias, very wellcontrolled impedances and electrical losses capable of achieving veryhigh data rates are provided.

Another possible implementation utilizing via technology would be in SiPwith vias through silicon. In this implementation, the second wafer 200is configured as a Silicon Photonics wafer. The electrical signals fromthe bottom third (electronic) wafer 300 comprising the electroniccomponents could either traverse from the top to the bottom of the third(electronic) wafer 300 or from the top of the third (electronic) wafer300 through the middle second (SiP optoelectronic) wafer 200 to the topfirst (opto-mechanical) wafer 100. The top of the electronic wafer 300would also be connected to the middle SiP optoelectronic wafer 200 inorder to drive the transmitter and receiver optoelectronic devices 210.In this implementation, the top opto-mechanical wafer 100 may optionallyhave electrical connectivity.

The specified method utilizes (GaAs, Si or other wafer-based) viafabrication technology to reduce parasitics of wirebondingoptoelectronic devices for III-V wafers and in other cases formulti-chip integration of Si-based electronic components. For thepurpose of the specified method, vias enable compact wafer-levelintegration of optical sources and detectors on a wafer, such as a GaAsor silicon photonics wafer, sandwiched between the third (bottom) wafer300 having electronic functions such as laser drivers and receiveramplifiers, for example Si CMOS or SiGe Bi—CMOS, and the first (top)wafer 100 having passive optical components, for example lenses, turningmirrors, fiber alignment components as well as possibly components forelectrical connectivity.

According to an embodiment of the method to manufacture theoptoelectronic modules, the wafer stack comprising the bonded first,second and third wafer 100, 200 and 300 may be diced along therespective metalized via holes 120 of the first module portions 101 ofthe first wafer 100 into the individual dies/optoelectronic modules 1 tocreate half- or castellated vias in the first wafer 100. As shown forthe optoelectronic module 1 of FIG. 4, vias 120 are arranged in thematerial of the first wafer 100 extending from the first surface S100 ato the second surface S100 b of the first wafer 100. In order toseparate the optoelectronic module 1, the first wafer 100 is dicedthrough the metalized vias 120 such that half- or castellated vias arecreated. The castellated vias could allow for perpendicular/edge bondingof the optoelectronic module as illustrated below in FIG. 8A.

FIG. 5 shows another embodiment of a wafer stack comprising the firstwafer 100, the second wafer 200 and the third wafer 300. In contrast tothe embodiment of the wafer stack shown in FIG. 2B, the first wafer 100is provided without any metalized vias through the first wafer 100 forbackside mounting. Fiber alignment components to hold and align theoptical fibers to the optical components 110 can be mounted on the firstwafer 100. According to another embodiment, the fiber alignmentcomponents can be configured as wafers stacked on top of the first wafer100. After being stacked and aligned the wafer stack is diced intoindividual optoelectronic modules.

According to a possible embodiment of the method to manufacture theoptoelectronic modules 1, a fourth wafer 400 configured for thermalisolation may be provided in method step D between the third wafer 300and the second wafer 200, wherein the fourth wafer 400 comprisesmetalized via holes in a material of the fourth wafer, wherein themetalized via holes are arranged to electrically couple the respectiveelectrical contact pads 330 of the third module portions 301 to therespective electrical contact pads 230 of the second module portions201. FIG. 6 shows an embodiment of a wafer stack comprising the firstwafer 100, the second wafer 200, the third wafer 300 and the fourthwafer 400.

The fourth wafer 400 serves as to improve thermal isolation of thesecond (optoelectronic) wafer 200 from the first (electronic) wafer 300.The insertion of the fourth wafer 400 allows to protect theoptoelectronic components 210, for example an optical source anddetector of the second wafer 200, from the electronic components 310,for example drive electronics of the third wafer. The fourth wafer 400may be configured as a glass interposer wafer with metal vias andredistribution layers between the third and the second wafers 300 and200. In this variation, the wafer stack up would include a total of fourwafers beginning at the bottom with the third (electronic) wafer 300,followed by the fourth wafer 400 acting as a thermal isolation wafer,the second (optoelectronic) wafer 200 and, at the top, the first(opto-mechanical) wafer 100. The isolation may especially be importantfor the VCSEL sub-assembly where the output optical power as well as thethreshold current is affected significantly by temperature especially asdata rates increase, but also may be important in SiP (SiliconPhotonics) where some devices are temperature sensitive.

FIG. 7 shows an embodiment of a wafer stack comprising just the firstwafer 100 and the second wafer 200. The first wafer 100 comprises firstmodule portions 101 comprising at least one passive optical component110 and metalized via holes 120. The second wafer 200 comprises thesecond module portions 201 comprising at least one optoelectroniccomponent and metalized via holes extending in the material of thesecond wafer 200. In contrast to the embodiment of the wafer stack shownin FIG. 2B, the wafer stack does not comprise the third wafer 300. Forthis embodiment, only one set of vias are needed, either in the firstwafer 100 or the second wafer 200, but not both. Vias in the first wafer100 would allow for downward or horizontal mounting as shown in FIG. 8B,9B or 11B, while vias in the second wafer 200 would allow for mountingas shown in FIG. 10b, 12a, 12b or 12 c.

FIGS. 8A to 12C show different arrangements of an optoelectronic module1 on an electronic board 3. The optoelectronic module 1 shown in FIGS.8A, 9A, 10A and 11A comprises the third substrate 300′ with electroniccomponents 310, such as drivers or amplifiers integrated in thesubstrate 300′, the second substrate 200′ with the optoelectroniccomponents 210, for example photodiodes or VCSELs, and the firstsubstrate 100′ with the passive optical components 110, such as opticallenses. The first substrate 100′ may also include electrical and/oropto-mechanical components. The second substrate 200′ containselectrical vias 220 to electrically couple the electronic components ofthe third substrate 300′ with the optoelectronic components of thesecond substrate. The electronic components and the optoelectroniccomponents may be electrically coupled to the electronic board by meansof electrical traces disposed on a surface of the first substrate 100′,as shown, for example, in the embodiments of FIGS. 8A, 9A and 11A. Inthe embodiment shown in FIG. 10A, there are no electrical contacts tothe first substrate 100′, but there are electrical vias in the thirdsubstrate 300′ to connect to the electronic board 3.

The optoelectronic module 1 shown in FIGS. 8B, 9B, 10B, 11B and 12A to12C only comprises the first substrate 100′ and the second substrate200′ but does not comprise the third substrate 300′. According to theembodiments shown in FIGS. 8B, 9B, 10B, 11B and 12A to 12C theelectronic components are provided as separate, individual devices 30directly mounted on the electronic board 3. The optoelectronic module 1is provided by dicing the wafer stack shown in FIG. 7 into individualmodules. The first substrate 100′ may or may not comprise electricalvias/metalized via holes. FIGS. 8b, 9b and 11b show embodiments withvias in the first substrate 100′ connecting the second substrate 200′.The vias on the first substrate 100′ can then connect to the electronicboard 3 by means of castellated vias (FIG. 8b ) or electronic contactpads (FIGS. 9b and 11b ). The electronic connection then provideselectrical connectivity between the second substrate 200′ and theelectronic components 30 being mounted on the electronic board 3. FIGS.10b and 12A to 12C show examples where the first substrate 100′ do notcomprise electrical vias/metalized via holes or any metal redistributionlayers. In the alternate embodiment, substrate 200′ comprises ofelectrical vias/metalized via holes in order to connect to theelectronic board 3 and, in particular, to the electronic components 30being mounted on the electronic board 3.

According to embodiments of an arrangement of the optoelectronic module1 on the electronic board 3, shown in FIGS. 8A and 8B, theoptoelectronic module 1 is perpendicularly attached onto the electronicboard 3. To this purpose, the first wafer 100 may comprise castellatedvias 110 as described above and shown in FIG. 4. Metal traces 10 may bearranged on the electronic board 3 to connect the optoelectronic module1, for example by means of the castellated vias, to electroniccomponents of the electronic board 2. Metallic pads, for example Cupads, may be optionally be provided on the backside of the electronicboard 3 for solder reflow to a master PCB, for example a motherboard. Aglue 20 may be applied to the surface of the electronic board 3 toprovide any stability for mounting the optoelectronic module 1 to theboard 3.

FIGS. 9A and 9B respectively show an embodiment of an arrangement of anoptoelectronic module 1 onto an electronic board 3, for example aprinted circuit board, wherein the optoelectronic module 1 is attacheddownward onto the electronic board 3. Metal traces 10 are provided on asurface of the electronic board 3 to electrically connect the electroniccomponents of the electronic board 3 to the optoelectronic module 1.

FIGS. 10A and 10B respectively show an embodiment of an arrangement ofan optoelectronic module 1 onto an electronic board 3, wherein theoptoelectronic module 1 is vertically mounted onto the electronic board3. The optoelectronic module 1 shown in FIG. 10A is provided by dicingthe wafer stack shown in FIG. 5 into individual modules. Theoptoelectronic module 1 shown in FIG. 10B is provided by dicing a waferstack only comprising the first wafer 100 and the second wafer 200,wherein the first wafer does not comprise electrical vias. The opticalfiber 2 is held and aligned by means of an alignment component, forexample, a fixture 160. The fixture 160 may be configured as anindividual component mounted/attached on the surface of the firstsubstrate 100′ or as a wafer/wafers with or without molded elementsstacked on top of the first substrate 100′.

FIGS. 11A and 11B respectively show an embodiment of a downwardarrangement of an optoelectronic module 1 onto an opto-electronic board3. Metal traces 10 are provided on a surface of the opto-electronicboard to electrically connect the electronic components of theopto-electronic board 3 to the optoelectronic module 1. Electrical viasare provided in the first substrate 100′ to make the electricalconnection between the electronic board 3 and the second substrate 200′(and the third substrate 300′ for the embodiment of FIG. 11A). Theopto-electronic board 3 may comprise a channel to insert a waveguide 4being embedded in the opto-electronic board 3 such that a front face ofthe embedded waveguide 4 is arranged in a cavity of the opto-electronicboard 3 under the passive optical component 110, for example a lens, ofthe optoelectronic module. Light may be coupled from the front face ofthe embedded waveguide 4 through the passive optical component 110 intothe optoelectronic module 1 and vice versa. To this purpose, theopto-electronic board 3 may comprises a mirror/TIR component to changethe direction in order to aid in the coupling of light.

FIGS. 12A to 12C show downward approaches of arrangements of anoptoelectronic module 1 comprising the first (opto-mechanical) substrate100′ and the second (optoelectronic) substrate 200′. The optoelectronicmodule 1 has no wafer-scale IC integration. The optoelectronic module 1has only a wafer-scale integration with the first (opto-mechanical)wafer 100 and the second (optoelectronic) wafer 200 and possibly with afiber alignment component made up of multiple wafers or moldedcomponents on a single wafer. The optoelectronic module 1 is provided bydicing the wafer stack as shown in FIG. 7 into individual modules. Theelectronic board 3 is provided with a cutout to place the optoelectronicmodule 1 to different components.

FIG. 12A shows an embodiment of an arrangement of an optoelectronicmodule 1 comprising the opto-mechanical substrate 100′ which can be madeof glass and the optoelectronic substrate 200′ on the electronic board3. The optoelectronic module 1 is electrically bonded onto theelectronic component 30, for example a transceiver. The optoelectronicsubstrate 200′ is disposed onto the electronic component 30. Theoptoelectronic substrate 200′ contains metallized via holes 220, i.e.electrical vias, to electrically couple the optoelectronic components ofthe optoelectronic substrate 200′ to the electrical component 30. Theelectrical component 30 is electrically coupled to the electronic board3.

FIG. 12B shows another embodiment of an arrangement of an optoelectronicmodule 1 comprising the opto-mechanical substrate 100′ which can be madeof glass and the optoelectronic substrate 200′ on the electronic board3. The optoelectronic module 1 is bonded onto an interposer 40 alongwith the electronic component 30, for example a transceiver. Theinterposer 40 comprises electrical vias 41 to electrically couple theoptoelectronic components of the optoelectronic substrate 200′ to theelectrical component 30 and electrical vias 42 to electrically couplethe optoelectronic components and the electrical component 30 to theelectronic board 3.

FIG. 12C shows another embodiment of an arrangement of an optoelectronicmodule 1 comprising the opto-mechanical substrate 100′ which can be madeof glass and the optoelectronic substrate 200′ on the electronic board3. The optoelectronic substrate 200′ is placed onto an electronicsubstrate 50. The optoelectronic components of the optoelectronicsubstrate 200′ are electrically coupled to the electronic board 3 viaelectrical traces of the electronic substrate 50. The electroniccomponent 30 is mounted to a side of the electronic board 3.

According to an embodiment of the method to manufacture theoptoelectronic modules, the first opto-mechanical wafer 100 may beprovided with mechanical elements to fix the optical fiber 2 to themodule 1 with high precision and exact alignment, thus creating a robustand well-aligned optical link. To this purpose, in method step A, arespective at least one fixture 160 fabricated from a wafer with moldedalignment features or a stack of wafers with varying sized vias may beplaced for each of the first module portions 101 on the first surfaceS100 a of the first wafer 100 to couple a respective at least oneoptical fiber 2 to the first module portions 101, as shown in FIGS. 8Ato 10B and in FIGS. 12A to 12C. The respective at least one fixture 160is configured to hold the respective at least one optical fiber 2 and toalign the respective at least one optical fiber 2 to the respective atleast one passive optical component 110 of the first module portions 101such that light is coupled between the respective at least one opticalfiber 2 and the respective at least one passive optical component 110 ofthe first module portions 101.

According to another embodiment of the method to manufacture theoptoelectronic components, the respective at least one fixture 160 isconfigured to provide a distance between a front face of the respectiveat least one optical fiber 2 coupled to the first module portions 101and the respective at least one passive optical component 110 of thefirst module portions 101.

The fixture may be made by wafer scale process molding directly onto thefirst wafer and/or is one of a single wafer and several stacked waferswith varying holes or molded elements to form the fixture and bonded tothe first wafer at the wafer scale.

FIGS. 8A to 12C show the fixture 160 being placed on the first surfaceS100 a of the first module portion 101 of the optoelectronic module 1 tohold and align the optical fiber 2 to the passive optical component 110.The fixture 160 may comprise protrusions 161 being configured to holdthe optical fiber 2 in a distance far away from the passive opticalcomponent 110. According to a possible embodiment, the fixture 160 canbe made of a single wafer with molded components. According to anotherembodiment, the fixture can be made of a stack of wafers with varyingsized holes and aligned to the first wafer 100 in the same fashion thatthe first wafer 100 is aligned to the second wafer 200. According toanother embodiment, the fixture 160 may comprise individual fixtureelements bonded precisely to each module.

For the majority of implementations described above, metal traces andvias on the first opto-mechanical wafer 100 are used to connect signalsto an external PCB. This concept is shown for example in FIGS. 2A and2B. The sub-assembly could be mounted onto a PCB perpendicular to itssurface as shown in FIGS. 8A and 8B.

Since the overall footprint of the optoelectronic modules can be reducedby stacking the second (optoelectronic) wafer 200 on top of the third(electronic) wafer 300 or IC, it is conceivable this implementationcould even work for applications with limited vertical space. An exampleof such an application is an active optical cable assembly in which thismodule would be integrated into the board residing in the plug of thecable.

Alternatively, the vias in the first opto-mechanical wafer 100 could bedesigned such that the metal connections are on the opposite side of thewafer and the module could be mounted horizontally as shown in FIGS. 9Aand 9B. In the horizontal arrangement, the electronic board 3 would needa cutout to allow for the optical path through the electronic board orit would need to be an optical PCB with embedded waveguides as shown inFIGS. 9A and 9B. By architecting the solution horizontally, it may bepossible to improve heat extraction and the electrical signalingcharacteristics. Such a solution may benefit applications where speed,power and heat are paramount, such as in data centers and server farms.

According to another embodiment of the method to manufacture theoptoelectronic modules, a spacer layer may be provided on the firstsurface S100 a of the first wafer 100 to provide a distance between afront face of the respective at least one optical fiber 2 coupled to thefirst module portions 101 and the respective at least one passiveoptical component 110 of the first module portions 101.

According to a further embodiment of the method to manufacture theoptoelectronic modules 1, the functionality of the bonded respectivefirst and second module portions 101, 201 and/or the bonded respectivethird and second module portions 301, 201 and/or the bonded respectivefirst and second and third module portions 101, 201, 301 is tested inthe method step D before dicing the wafer stack into the individualdies. According to another embodiment, the functionality of theoptoelectronic modules is tested before dicing the bonded first, secondand third wafer in method step E into the individual dies/optoelectronicmodules.

In order to make the final optoelectronic module compatible to SMT(Surface Mounted Technology), the respective materials of the first,second and third wafer must be chosen appropriately and a coveringelement could be needed over the optical and mechanical alignmentfeatures to prevent debris from compromising that area. According to apossible embodiment of the method to manufacture the optoelectronicmodules, the covering element may be placed on the first surface S100 aof the first wafer 100 to protect the respective at least one passiveoptical component 110 of the first module portions 101 from debris whendicing the wafer stack into the individual dies and/or to assist withfiber alignment. Alternatively a cleaning step may be used in place of aprotective cover.

The covering element could prove useful during the dicing process of thewafer as well as during SMT. Thus, the cover should be placed prior tosingulation (at the wafer-scale) and removed following the entire SMTprocess and just before fiber insertion. Additionally, the cover couldbe placed back onto the module following fiber insertion to addmechanical support and alignment of the fiber.

The integration of the three wafers, i.e. the bottom electrical, themiddle optoelectronic and the top opto-mechanical wafers 300, 200 and100 provides many possible benefits. One benefit is the compactintegration of the second (optoelectronic) wafer 200, for example GaAsVCSEL or silicon photonics wafer, with the third (bottom electrical)wafer 300, which leads to very well controlled impedances and parasiticscritical for data rates above 10 Gbps.

A second benefit is the tight alignment accuracies and parallelism ofalignment over hundreds to thousands of modules of the first(opto-mechanical) wafer 100 to the second (optoelectronic) wafer 200,critical for high-speed multi-mode as well as single-mode operation. Athird benefit is the capability to have easy access to electricalsignals external to the module either by vias through the second(optoelectronic) wafer 200 connecting the top of the third (electronic)wafer 300 to the first (opto-mechanical) wafer 100 or alternatively viasthrough the third (electronic) wafer 300 connecting the top to thebottom of the third wafer 300.

A fourth benefit is the compact size of the entire subassemblies afterdicing the wafer-stack of the first, second and third wafer. A fifthbenefit is the compatibility of a final optoelectronic module withtraditional electronic processing technologies, such as Surface MountTechnology (SMT). A sixth benefit is that the platform can be used forboth multi-mode and single-mode optical integration given the very tightoptical alignment tolerances, allowing for use with traditionalVCSEL-based multi-mode optics as well as Silicon Photonics (SiP)single-mode optics with all light emission is surface normal. Andlastly, these optoelectronic subassemblies have the further capabilityof wafer-scale testing to produce “known-good modules”.

The method to manufacture optoelectronic modules is described in thefollowing by process steps for manufacturing an optoelectronic receivermodule using the first opto-mechanical wafer 100, the secondoptoelectronic wafer 200 and the third electronic wafer 300, wherein aGaAs approach is assumed to be used for the second wafer 200.

According to a first method step, the electronic wafer 300 is designedwith module portions 301 respectively comprising a receiver integratedcircuit (IC) and top electrical pads having a pitch easily fabricated ona low-cost electronic circuit substrate, for example a PCB. An examplepitch would be 0.25 mm where the pads and spacing widths are 0.125 mm.Variation of this design is valid presuming the electrical signalintegrity is good and the integration onto an electronic board remainsfeasible.

In a subsequent step the optoelectronic wafer 200 is designed withsecond module portions 201 respectively comprising a GaAs photodiodewith pad locations, spacing and widths that match the receiver IC andthrough GaAs vias to replicate the location, spacing and widths of theelectrical pads on the backside of the optoelectronic GaAs wafer 200.

After fabrication of the electronic and optoelectronic wafers,thermo-compression or other means may be applied to electrically bondthe optoelectronic GaAs wafer 200 onto the electronic wafer 300, andalign the electrical pads on the top surface of the electronic wafer 300to the pads on the bottom surface of the optoelectronic GaAs wafer 200.

Some of the electrical pads on the top surface of the optoelectronicGaAs wafer 200 need only connect to the bottom electronic wafer 300, forexample those that connect to the photodiode, while other pads need toconnect eventually to the electronic board, for example a PCB. Thelayout of the pads and the subsequent metal redistribution layer on theglass substrate should reflect that connection requirement.

According to a subsequent step, the stacked wafers 300 and 200 aretested for optical and electrical functionality, for example, by usingan optical and electrical probe system.

The electrical portion of the opto-mechanical wafer 100 may be designedwith an electrical redistribution layer from trace pads aligned to theoptoelectronic GaAs wafer 200 top surface to metalized vias in theglass. The vias should be designed such that dicing would occur throughthe via and provide sufficient metal remaining in the half- orcastellated-via to create contacts in a perpendicular orientation.

Alternatively, the vias could be of the non-castellated type and flippedonto a PCB. Following the electrical design, opto-mechanical componentsincluding polymer lenses, spacer layers, mechanical alignment featuresto align optical fibers to the lenses and provide an optimized opticalpath are designed. After the design phase, the opto-mechanical wafer 100can be fabricated by the steps of creating through-glass vias (TGVs),metalizing glass vias, metalizing glass redistribution layer and contactpads, plating up metal lines and contacts as needed, molding polymerlenses on alternate side, optionally placing a spacer layer, optionallyplacing an optical turn, placing fiber alignment features and placingmechanical fixturing features for the fiber holder, all of which may bedone at the wafer scale.

In a subsequent step thermo-compression or other means of electricalbonding is provided to bond the top surface of electronic/optoelectronicwafer stackup onto the metalized side of the opto-mechanical wafer 100so that the photodiodes are aligned with the lenses within lowtolerance, for example an accuracy of less than 2 μm. Additionally, anindex matching gel can be placed between the photodiode surface and theglass to minimize reflections on the surfaces.

The modules may be tested on the wafer-scale before dicing, wherein anymay be marked that fail to meet manufacturing standards for electricaland optical connectivity. After the testing, a removable wafer-scalecovering element may be placed over the opto-mechanical features on thetop surface of the opto-mechanical wafer 100. The stacked wafers 300,200 and 100 are then diced into individual optoelectronic modules,cleaned and the temporary covering element is removed.

The singularized final optoelectronic modules may be visually tested andadditionally tested in a test fixture for good electrical and opticalconnectivity for perpendicular, vertical or downward surface mounting toa PCB. Afterwards, the temporary covering element is replaced forshipping and as a possible final fiber alignment mechanical fixture.

One alternative process flow in which the electronic wafer 300 is notpart of the optoelectronic module as shown for the wafer stack in FIG. 7would change a few of the steps described above. The first step wouldchange such that some or possibly none of the metal pads on the IC needmatch the GaAs substrate of the optoelectronic wafer. The step ofbonding the electronic and the optoelectronic wafer would be removed.According to a possible embodiment, the steps of designing andfabricating the opto-mechanical wafer 100 would not need any of themetallization described. The opto-mechanical wafer could still havemetallization in some embodiments as shown in FIGS. 8B, 9B and 11B, andhave it mounted on the side or flip chipped and with the silicon IC onthe electronic board or glass interposer instead of in the stack up. Thestep of bonding the opto-mechanical wafer 100 onto the optoelectronicwafer 200 could only need index matching epoxy and no electricalconnection according to a possible embodiment. After the step of testingthe optoelectronic module and replacing the temporary cover, anadditional step is needed to apply thermo-compression, or by othermeans, mount the optoelectronic module onto an electronic wafer for goodelectrical connection.

Alternatively, the last step could be to mount the optoelectronic moduleonto a glass interposer with the electronic chip mounted to the backsideor to the side for thermal isolation or to a common substrate, such as aPCB. The final module would then be tested for electrical and opticalperformance. These possible embodiments are represented in FIGS. 12A to12C.

Alternatively, the last step could be to mount the optoelectronic moduleto the final electronic board 3 with the electronic chip mounted to theside as shown in FIGS. 8B, 9B, 10B and 11B.

For the silicon photonics process, the same steps above could be usedwith the GaAs wafer 200 replaced by a silicon photonics wafer 200.Additionally, it would be possible to integrate both receiver andtransmitter functionality onto one wafer rather than having two separateprocess flows. The silicon photonics process could also be slightlyaltered such that the electrical tracing going externally to anelectronic board goes through the electronic wafer rather than throughthe SiP wafer to the opto-mechanical wafer. In this process flow, thefirst step of designing the electronic wafer 300 would also need todesign through Si vias to the backside to match with standard PCB orsimilar electronic board capabilities. The steps of designing andfabricating the opto-mechanical wafer 100 would not need any of themetallization described for the opto-mechanical wafer. The step ofbonding the opto-mechanical wafer 100 to the optoelectronic wafer 200would only need index matching epoxy and no electrical connection.According to another possible embodiment, the opto-mechanical wafer 100may still have the electronic connection through the opto-mechanicalwafer with the Silicon IC chip either disposed on a common substrate orthe stacked up module bonded onto the Silicon IC, where the IC is alarger chip than the module.

Another variation to the method to manufacture optoelectronic modulescould be a mix of wafer-level integration with chip-based integrationused in silicon-based electronics. In this implementation, wafer-levelintegration of just the two top wafers, i.e. the optoelectronic wafer(GaAs, SiP or other) 200 and the opto-mechanical wafer 100, isperformed. In this case, the two wafers 100 and 200 would be bondedsolely with index-matching epoxy and have no electrical connectivitywhile still maintaining the advantages of wafer-level fabrication forthe optical and fiber attach elements. According to another embodiment,it is possible to consider having metalization here for downward or flipchip connections as well, for example, either through metalredistribution layers and/or vias. The arrangement is shown in FIGS. 8B,9B, 10B and 11B with the IC mounted on the PCB, or as shown below inFIG. 14 where the surface S200 b of the optoelectronic wafer would havea metal redistribution layer in order to connect the VCSELs, PDs andDriver/Receiver circuitry.

This two-layer stack would form the sub-assembly to then be diced intoindividual optoelectronic modules, which can be electrically connectedat the bottom of the module, i.e. the bottom of the optoelectronicwafer, using the same via design as the previous three-layer stack.Since the two-layer stack no longer directly integrates the electronicwafer functionality into the wafer-level integration, it is necessary tosubsequently integrate the singularized optoelectronic module, i.e. thediced two-layer stack, with an electronic chip or a diced electronicwafer. One possible method to do this final integration with anelectronic chip could be to bond the optoelectronic module directly ontop of an electronic chip or an interposer substrate typically referredto as 2.5D or 3D integration in silicon processing. Alternatively, themodule could be soldered, e.g. through Surface Mount Technology (SMT),directly to an electronic board, such as a PCB, with nearby electronicchips with laser drive and receiver amplification.

Embodiments of a method to manufacture the optoelectronic modulescomprising at least two substrates cut out of a wafer stack comprisingat least the first (opto-mechanical) wafer 100 and the second(optoelectronic) wafer 200 are described with reference to FIGS. 13A and13B.

FIG. 13A shows a wafer stack comprising the first (opto-mechanical)wafer 100 comprising alignment components 160, such as v-grooves, andlight turning elements 170 based on TIR (Total Internal Reflection). Thefirst wafer 100 does not comprise any electrical vias through thematerial of the first wafer 100, for example a glass material. The waferstack further comprises a spacer wafer 600 bonded below theopto-mechanical wafer 100 and the second (optoelectronic) wafer 200arranged on the bottom side of the spacer wafer 600. The optoelectronicwafer 200 can be made of glass. Electronic components, for example atransceiver, and optoelectronic components, for example, a VCSEL and/ora PD can be placed on a surface of the optoelectronic wafer 200.

FIG. 13B shows a wafer stack comprising an opto-mechanical wafer 100, aspacer wafer 600 and an optoelectronic wafer 200. The opto-mechanicalwafer 100 is placed on the top side of the wafer stack and theoptoelectronic wafer 200 is placed on the bottom side of the waferstack. The spacer wafer 600 is arranged between the opto-mechanicalwafer 100 and the optoelectronic wafer 200. The optoelectronic wafer 200may be configured as an electronic board, for example a PCB withindividual electronic and opto-electronic components arranged on top ofthe electronic board within an opening of the spacer wafer as shownbelow in FIG. 19. Alternatively, the optoelectronic wafer 200 may beconfigured as a SiP wafer with backside electrical connections.

According to an embodiment of a method to manufacture optoelectronicmodules, a wafer stack as shown in FIG. 13A is provided. The wafer stackcomprises a first (opto-mechanical) wafer 100 comprising a plurality offirst (opto-mechanical) module portions 101, wherein each of the first(opto-mechanical) module portions 101 comprises at least one fixture160, which is molded at the wafer scale onto the surface of the firstwafer 100, to hold an optical fiber 2. Alternatively, the fixture canalso be individual injection molded elements that are bonded preciselyto each module.

Embodiments of a method to manufacture optoelectronic modules as well asthe corresponding optoelectronic modules are described below withreference to FIGS. 14 to 19 showing the corresponding optoelectronicmodules manufactured by the method. According to an embodiment of themethod to manufacture the optoelectronic modules, a first(opto-mechanical) wafer 100 comprising a plurality of first moduleportions 101 is provided, wherein the first wafer 100 has a firstsurface S100 a and an opposite second surface S100 b. A second(optoelectronic) wafer 200 comprising a plurality of second moduleportions 201 is provided, wherein the second wafer 200 has a firstsurface S200 a and an opposite second surface S200 b. Each of the secondmodule portions 201 comprises at least one optoelectronic component 210.

The first wafer 100 is disposed onto the second wafer 200 to provide awafer stack such that the second surface S100 b of the first wafer 100is placed opposite to the first surface S200 a of the second wafer 200and each of the first module portions 101 is aligned to a respective oneof the second module portions 201 so that light coupled in a respectiveone of the first module portions 201 is transferred to a respective oneof the second module portions 201 and is directed to the respective atleast one optoelectronic component 210 of the second module portions201. The wafer stack is diced into individual dies respectivelycomprising one of the first (opto-mechanical) and one of the second(optoelectronic) module portions for respectively forming one of theoptoelectronic modules 1.

According to a possible embodiment of the method to manufacture theoptoelectronic modules, each of the first module portions 101 comprisesat least a fixture 160 to hold an optical fiber 2. The at least onefixture 160 is made by a wafer scale process molding directly onto thefirst wafer 100 and/or using one of a single wafer with molded elementsand several stacked wafers with varying holes and/or cut outs.

According to another possible embodiment of the method to manufacturethe optoelectronic modules, at least one passive optical component 110for each of the first module portions is provided on the first surfaceS100 a of the first wafer 100. The first wafer 100 is disposed onto thesecond wafer 200 such that light coupled into the respective at leastone passive optical component 110 of the first module portions 101 iscoupled into the respective at least one optoelectronic component 210 ofthe second module portions 201.

According to another possible embodiment of the method to manufacturethe optoelectronic modules, at least one of the first and second moduleportions 101, 201 is provided with at least one passive opticalcomponent 110 a, 110 b. The first wafer 100 is disposed onto the secondwafer 200 to provide a wafer stack such that each of the first moduleportions 101 is aligned to a respective one of the second moduleportions 201 so that light coupled out of the optical fiber 2 held inthe respective at least one fixture 160 of the first module portions 101is coupled into the respective at least one passive optical component110 a, 110 b of one of the first and second module portions 101, 201 atthe first side of the respective at least one passive optical componentand is coupled out at the second side of the respective at least oneoptical component and is directed to the respective at least oneoptoelectronic component 210 of the second module portions 201.

According to another possible embodiment of the method to manufacturethe optoelectronic modules, a respective one of the at least one passiveoptical component 110 a for each of the first module portions 101 isplaced on the second surface S100 b of the first wafer 100. Therespective at least one optoelectronic component 210 of the secondmodule portions 201 is placed on the first surface S200 a of the secondwafer 200.

According to another possible embodiment of the method to manufacturethe optoelectronic modules, a respective one of the at least one passiveoptical component 110 b for each of the second module portions is placedon the first surface S200 a of the second wafer 200. The respective atleast one optoelectronic component 210 of the second module portions 201is placed on the second surface S200 b of the second wafer 200.

According to another possible embodiment of the method to manufacturethe optoelectronic modules, a respective first one of the at least onepassive optical component 110 a for each of the first module portions101 is placed on the second surface S100 b of the first wafer 100. Arespective second one of the at least one passive optical component 110b for each of the second module portions 201 is placed on the firstsurface S200 a of the second wafer 200. The respective at least oneoptoelectronic component 210 of the second module portions 201 is placedon the second surface S200 b of the second wafer 200.

According to another possible embodiment of the method to manufacturethe optoelectronic modules, the first wafer 100 is provided with arespective at least one light turning element 170 for each of the firstmodule portions 101. The light turning element 170 is configured tochange a direction of the light beam so that light is coupled betweenthe respective one of the at least one optical fiber 2 coupled to thefirst module portions 101 and the respective at least one passiveoptical component 110 a, 110 b of the at least one first and secondmodule portions 101, 201.

According to another possible embodiment of the method to manufacturethe optoelectronic modules, at least one respective electronic component310 is provided for each of the second module portions 201. Therespective at least one electronic component 310 is placed on one of thefirst and second surface S200 a, S200 b of the second wafer 200.

According to another possible embodiment of the method to manufacturethe optoelectronic modules, a covering element 500 is provided over thefirst surface S100 a of the first wafer 100.

According to another possible embodiment of the method to manufacturethe optoelectronic modules, a spacer wafer 600 is provided between thefirst wafer 100 and the second wafer 200. Alternatively, a spacer layermade by molding directly onto the first surface S200 a of the secondwafer 200 and/or the second surface S100 b of the first wafer 100 may beprovided.

According to another possible embodiment of the method to manufacturethe optoelectronic modules, respective tapered and/or straight etchedholes 190 are provided for each of the first module portions 101 in thematerial of the first wafer 100 to fix the front face of the respectiveat least one optical fiber 2 coupled to the first module portions 101 ofthe first wafer 100. Alternatively, respective straight holes andrespective molded tapers for each of the first module portions 101 maybe provided in the material of the first wafer 100 to fix the front faceof the respective at least one optical fiber 2 coupled to the firstmodule portions 101 of the first wafer 100.

According to a possible embodiment of the method to manufacture theoptoelectronic modules, either the first and second wafers 100, 200 arerespectively configured as glass wafers, or the first wafer 100 isconfigured as a glass wafer and the second wafer 200 is configured asone of a printed circuit board, ceramic substrate, electronic board andan SiP wafer.

The respective at least one passive optical component 110, 110 a, 110 bof one of the first and second module portions 101, 201 may comprise anoptical lens. The respective at least one optoelectronic component 210of the second module portions 201 may be configured as an opticalemitter and/or an optical receiver. The respective at least oneelectronic component 310 of the second module portions 201 may beconfigured as an electrical driver and/or an electrical amplifier.

Several embodiments of an optoelectronic module comprising at least twostacked substrates, for example a first (opto-mechanical) substratecomprising optical components such as optical alignment components andbeam deflection components and a second (optoelectronic) substratecomprising electronic and optoelectronic components such as transceiverICs, VCSELs or PDs being cut out of the wafer stack of the bondedoptoelectronic wafer 200 and an opto-mechanical wafer 100 are shown inFIGS. 14 to 19. The optoelectronic modules shown in FIGS. 14 to 19additionally comprise other components, for example a spacer polymer.The spacer polymer could be a wafer in itself and thus many of theembodiments shown in FIGS. 14 to 19 may be based on 2-4 stacked wafers,as for example shown for the 3 stacked wafers of FIGS. 13A and 13B.

FIG. 14 shows an exploded view of an optoelectronic module 1manufactured with the method as described with reference to the waferstack shown in FIG. 13A. The optoelectronic module comprises anopto-mechanical substrate 100′, an optoelectronic substrate 200′ and aspacer layer 180 that are cut out of the bonded wafer stack comprisingthe opto-mechanical wafer 100, the optoelectronic wafer 200 and thespacer wafer 600 as shown in FIG. 13A. A covering element 500 isprovided to be disposed on the first surface S100 a of theopto-mechanical substrate 100′.

A fixture 160 to hold the optical fibers 2 is arranged on the firstsurface S100 a of the opto-mechanical substrate 100′. A light turningelement 170 including a fiber alignment structure is placed on the firstsurface S100 a of the opto-mechanical substrate 100′. The light turningelement 170 is either molded directly onto the surface or placed withprecision and created using injection molding. First passive opticalcomponents 110 a, for example lenses, are placed on the second surfaceS100 b of the opto-mechanical substrate 100′. Spacer layers 180 areprovided, wherein the spacer layers 180 may be placed on the secondsurface S100 b of the opto-mechanical substrate 100′ or on the firstsurface S200 a of the optoelectronic wafer 200 or both surfaces S100 band S200 a. It is also possible to provide a separate spacer wafer invarious manufacturing stackups. The opto-mechanical substrate 100′ maybe configured as a glass substrate. The light turning element 170 withthe fiber alignment structure may be configured as a molded polymerlayer, and the first passive optical components 110 a may be configuredas another molded polymer layer and the spacer layers 180 may be moldedas another polymer or a separate machined wafer and disposed on theglass substrate 100′ fabricated as one component.

The optoelectronic substrate 200′ may comprise second passive opticalcomponent 110 b being disposed on a first surface S200 a of theoptoelectronic substrate 200′. The second passive optical components 110b may be configured as one molded polymer layer being disposed on aglass substrate 200′. The optoelectronic substrate 200′ furthercomprises electronic components 310, such as transceivers. Solder ballcontacts 230 to reflow the module on a PCB substrate and a metallizationfor an optoelectronic component 210, for example a VCSEL or a PD, aredisposed on the second surface S200 b of the optoelectronic substrate200′.

FIG. 15A shows a two-dimensional exploded view of the optoelectronicmodule 1 as shown in FIG. 14 in a perspective exploded view. FIG. 15Bshows an embodiment of an optoelectronic module 1 of FIG. 15Amanufactured with the method described with reference to the wafer stackshown in FIG. 13A. The optoelectronic module comprises anopto-mechanical substrate 100′, an optoelectronic substrate 200′ and aspacer layer 180 that are cut out of the bonded wafer stack comprisingthe opto-mechanical wafer 100, the optoelectronic wafer 200 and thespacer wafer 600 as shown in FIG. 13A. The opto-mechanical substrate100′ and the optoelectronic substrate 200′ may be made of glass beingtransparent for the light transferred in the optical fiber 2. A coveringelement 500 that can be made of glass or plastic is disposed on thefirst surface S100 a of the opto-mechanical substrate 100′.

A fixture 160 to hold the optical fiber 2 is arranged on the firstsurface S100 a of the opto-mechanical substrate 100′. Light turningelements 170 a and 170 b are disposed on the first surface S100 a of theopto-mechanical substrate 100′. First passive optical components 110 a,for example lenses, are placed on the second surface S100 b of theopto-mechanical substrate 100′. Spacer layers 180 are placed on thesecond surface S100 b of the opto-mechanical substrate 100′ and on thefirst surface S200 a of the optoelectronic substrate 200′. Theopto-mechanical substrate 100′ may be configured as a glass substrate.

The optoelectronic substrate 200′ comprises second passive opticalcomponents 110 b, for example lenses, being disposed on the firstsurface S200 a of the optoelectronic substrate 200′. The optoelectronicsubstrate 200′ further comprises electronic components 310, such astransceivers. Solder ball contacts 230 to reflow the module on a PCBsubstrate and optoelectronic components 210, for example a VCSEL or aPD, are disposed on the second surface S200 b of the optoelectronicsubstrate 200′.

The optoelectronic module 1 has a first optical path comprising thelight turning element 170 a and the optical lens 110 a. Light coupledout of the optoelectronic component 210 a being configured as a VCSEL iscoupled out of the VCSEL 210 a and coupled in the lens 110 a. The lightis coupled through the opto-mechanical substrate 100′ into the lightturning element 170 a from which it is deflected towards the opticalfiber 2. The optoelectronic module 1 has a second optical pathcomprising the light turning element 170 b and the optical lens 110 b.Light coupled out of the optical fiber 2 is deflected by the lightturning element 170 b through the opto-mechanical substrate 100′ towardsthe optical lens 110 b. The lens 110 b focuses the light to theoptoelectronic component 210 b that can be configured as a photodiode.

FIGS. 16A and 16B respectively show other embodiments of anoptoelectronic module 1 manufactured with the method described withreference to the wafer stack shown in FIG. 13A. The optoelectronicmodules shown in FIGS. 16A and 16B comprise an opto-mechanical substrate100′ and an optoelectronic substrate 200′ that are cut out of the bondedwafer stack comprising the opto-mechanical wafer 100 and theoptoelectronic wafer 200 as shown in FIG. 13A The opto-mechanicalsubstrate 100′ may be made of a material being opaque for the lighttransferred in the optical fiber 2. A covering element 500 that can bemade of glass or plastic is disposed on the first surface S100 a of theopto-mechanical substrate 100′.

The optoelectronic module 1 shown in FIG. 16A comprises the samearrangement of the fixture 160 and the light-turning elements 170 a, 170b on the first surface S100 a of the opto-mechanical substrate 100′ andfirst passive optical components 110 a, for example lenses, as well asspacer layers 180 on the second surface S100 b of the opto-mechanicalsubstrate 100′ as shown in FIG. 15A.

The optoelectronic substrate 200′ comprises the same arrangement of thesecond passive optical components 110 b, for example lenses, and spacerlayers 180 on the first surface S200 a of the optoelectronic substrate200′ and electronic components 310, such as transceivers, solder ballcontacts 210 and optoelectronic components 210, for example a VCSEL or aPD, on the second surface S200 b of the optoelectronic substrate 200′ asshown for the optoelectronic module in FIG. 15A.

The opto-mechanical substrate 100′ may comprise cavities 101 within theopaque material of the opto-mechanical substrate 100′. The cavities maybe filled with a material of polymer to provide a light transmissionpath between the light turning elements 170 a, 170 b and the first andsecond passive optical components 110 a and 110 b.

FIG. 16B shows a similar embodiment of an optoelectronic module as shownin FIG. 16A with the difference that first passive optical components110 a and second passive optical components 110 b, such as lenses, aredisposed opposite to each other on the second surface S100 b of theopto-mechanical substrate 100′ and the first surface S200 a of theoptoelectronic substrate 200′. Additional embodiments not shown can havethe optical components placed in other configurations, such as both onsurface S100 b or both on surface S200 a.

FIGS. 17A and 17B respectively show an embodiment of an optoelectronicmodule 1 manufactured with the method described with reference to thewafer stack shown in FIG. 13A. The optoelectronic module comprises anopto-mechanical substrate 100′ and an optoelectronic substrate 200′ thatare cut out of the bonded wafer stack comprising the opto-mechanicalwafer 100 and the optoelectronic wafer 200 as shown in FIG. 13A. Theopto-mechanical substrate 100′ and the optoelectronic substrate 200′ maybe made of glass being transparent for the light transferred in theoptical fiber 2. The top substrate 100′ acts as supporting means for theopto-mechanical components and additionally as a cover. The lightturning elements 170 a, 170 b acts as mirrors having a metal or similarcoating to be reflective.

Light turning elements 170 a and 170 b as well as a fiber alignmentfixture 160 are arranged on the second surface S100 b of theopto-mechanical substrate 100′. Passive optical components 110 a, 110 bas well as a vertical adjustment polymer layer 250 are disposed on thefirst surface S200 a of the optoelectronic substrate 200′. The verticaladjustment polymer layer 250 can be a portion of the spacer wafer 600.The optoelectronic substrate 200′ further comprises electroniccomponents 310, such as transceivers, solder ball contacts 230 to reflowthe module on a PCB substrate and optoelectronic components 210, forexample a VCSEL or a PD, that are disposed on the second surface S200 bof the optoelectronic substrate 200′.

The optoelectronic module 1 shown in FIG. 17B is embodied in a similarway as shown for the optoelectronic module of FIG. 17A with thedifference that a curvature is added to the light turning elements 170 aand 170 b being configured as metal coated mirrors.

FIGS. 18A to 18C respectively show embodiments of an optoelectronicmodule 1 manufactured with the method described with reference to thewafer stack shown in FIG. 13A. The optoelectronic module comprises anopto-mechanical substrate 100′ and an optoelectronic substrate 200′ thatare cut out of the bonded wafer stack comprising the opto-mechanicalwafer 100 and the optoelectronic wafer 200 as shown for the wafer stackin FIG. 13A.

The opto-mechanical substrate 100′ comprises cavities 101 to insertoptical fibers 2. Spacer layers 180 are disposed on the first and secondsurface S100 a and S100 b of the opto-mechanical substrate 100′. Theoptoelectronic substrate 100′ can be made of glass being transparent forthe light transferred through the optical fiber 2 and for arrangingelectrical traces. First and second passive optical components 110 a and110 b, for example lenses, are disposed on the first surface S200 a ofthe optoelectronic substrate 200′. The optoelectronic substrate 200′further comprises electronic components 310, such as transceivers,solder ball contacts 230 to reflow the module on a PCB substrate andoptoelectronic components 210, for example a VCSEL or a PD, that aredisposed on the second surface S200 b of the optoelectronic substrate200′. The optoelectronic components and the electronic components arearranged on the same substrate for electrical integrity.

The opto-mechanical substrate 100′ may be made of glass, wherein thecavities 101 are configured as tapered etched holes 190. According tothe embodiment of the optoelectronic module shown in FIG. 18A, theoptical fibers 2 are inserted in the tapered etched holes. According tothe embodiment of the optoelectronic module shown in FIG. 18B, theopto-mechanical substrate 100′ is configured to be made of a materialbeing opaque for the light transferred through the optical fibers 10.The opto-mechanical substrate 100′ comprises cavities 101 formed astapered polymer molded holes 190 in which the optical fibers 2 areinserted. The optoelectronic module 1 shown in FIG. 18C is embodiedsimilar as shown for the optoelectronic module of FIG. 18B with thedifference that the polymer molded holes do not taper and are providedwith a hard cladding or ferrule 5 acting a fiber stop means.

FIG. 19 shows an embodiment of an optoelectronic module 1 comprising theopto-mechanical substrate 100′ and the optoelectronic substrate 200′. Incontrast to the embodiments shown in FIGS. 14 to 18C the optoelectroniccomponents, such as VCSEL/PD, are wirebonded onto an optoelectronicwafer 200 being embodied as a PCB or similar electronic board withelectrical traces and vias to connect this module externally to a largerPCB or electronic board later after dicing. The stack arrangement ismanufactured at the wafer scale with the PCB being a wafer.

The substrate 100′ may be made of glass having a first surface S100 a onwhich a fixture 160 for holding and aligning an optical fiber 2 andlight turning elements 170 a, 170 b are disposed. A cap 500 made ofglass or a plastic material is disposed on the first surface S100 a ofthe opto-mechanical substrate 100′. Passive optical components 170, suchas lenses, are disposed on a second surface S100 b of theopto-mechanical substrate 100′.

The opto-mechanical substrate 100′ is mounted onto the optoelectronicsubstrate 200′, for example a PCB. The optoelectronic substrate 200′comprises optoelectronic components 210 a, 210 b being embodied asVCSELs or PDs and arranged on a first surface S200 a of theoptoelectronic substrate. An electronic component 310, for example atransceiver IC, may also be mounted onto the first surface S200 a of theoptoelectronic substrate 200′. Electrical contact pads are provided onthe second surface S200 b of the optoelectronic substrate 200′. A spacerlayer 180 is arranged between the second surface S100 b of theopto-mechanical substrate 100′ and the first surface S200 a of theoptoelectronic substrate 200′. The scale unit given in FIG. 19 is just apossible orientation and does not restrict the components of theembodiment to the specified values.

The opto-mechanical substrate 100′ is aligned to the optoelectronicsubstrate 200′ at the wafer scale so that light may be transferredthrough a first optical path from the optoelectronic transmitter 210 athrough the lens 110 a and the glass substrate 100′ to the light turningmirror 170 a that deflects the light such that it is coupled into theoptical fiber 2. The opto-mechanical substrate 100′ is further alignedto the optoelectronic substrate 200′ so that light may be transferredthrough a second optical path from the optical fiber 2 to the lightturning mirror 170 b that deflects the light towards the lens 110 b fromwhich the light is coupled out towards the optoelectronic receiver 210b.

In conclusion, the different embodiments of the method to manufactureoptoelectronic components substantially reduce the cost of assemblingdevices comprising electronic integrated circuits, optoelectronicsources and detectors, optical components and waveguides such as lensesand fiber. The embodiments of the method allow fabricating multipledevices in parallel and aligning them at the wafer-scale therebyincreasing assembly throughput. Testable sub-assemblies are fabricatedby dicing the stacked wafers that allows verification of the criticalprecision alignments and device functionality prior to additionalassembly thereby reducing the loss of other components due to fallout.The optoelectronic sub-assemblies built by the described embodiments ofthe method are compatible with low cost electronic circuit boardfabrication technology, such as surface-mount technology (SMT). Theembodiments of the method provide a path toward high-speed assembly atlow-cost due to tight alignment tolerances and controlled electricalconnectivity and allow volume manufacturing that can scale cost down asdemand increases. Furthermore, the need for wirebonding in someembodiments is eliminated which improves impedance control of theelectrical lines as well as vibration tolerance for automotive or othersuch applications.

Another benefit to the specified approach is that the placement of theoptical emitter/receiver can be nearly anywhere in the plane of themodule instead of near the perimeter as in many pick-and-place designswhere the electronic chip and optoelectronic chips are on a commonsubstrate. With this freedom, the likely ideal placement would be towardthe center of the module so that the mechanical features holding thefiber in alignment can also be centered.

We claim:
 1. A method to manufacture optoelectronic modules, comprising:providing a first wafer comprising a plurality of first module portions,wherein each of the first module portions comprises at least one passiveoptical component, wherein the at least one passive optical componenthas a first and a second side and is configured to modify a beam oflight such that a direction of light coupled in the at least one passiveoptical component at the first side is changed and coupled out of the atleast one passive optical component at the second side; providing asecond wafer comprising a plurality of second module portions, whereineach of the second module portions comprises at least one optoelectroniccomponent and metalized via holes extending in a material of the secondwafer from a first surface of the second wafer to a second oppositesurface of the second wafer, wherein the respective at least oneoptoelectronic component of the second module portions is electricallyconnected to the respective metalized via holes of the second moduleportions; providing a third wafer comprising a plurality of third moduleportions, wherein each of the third module portions comprises at leastone electronic component; bonding the second wafer onto the third wafersuch that the respective at least one electronic component of the thirdmodule portions is electrically coupled to the respective at least oneoptoelectronic component of the second module portions by means of therespective metalized via holes of the second module portions; bondingthe first wafer onto the second wafer to provide a wafer stack such thateach of the first module portions is aligned to a respective one of thesecond module portions so that light coupled into the respective atleast one passive optical component of the first module portions at thefirst side of the respective at least one passive optical component iscoupled out at the second side of the respective at least one passiveoptical component and is directed to the respective at least oneoptoelectronic component of the second module portions; and dicing thewafer stack into individual optoelectronic modules respectivelycomprising one of the first and the second and the third moduleportions.
 2. The method of claim 1, comprising: the first wafer having afirst and a second surface being opposite to the first surface;arranging the at least one passive optical component of each of thefirst module portions on the first surface of the first wafer; providingthe second wafer with the at least one optoelectronic component of eachof the second module portions being arranged on the first surface of thesecond wafer; and bonding the first wafer onto the second wafer suchthat the second surface of the first wafer is disposed on the firstsurface of the second wafer.
 3. The method of claim 1, comprising:providing the third wafer with respective electrical contact pads foreach of the third module portions on a first surface of the third wafer,wherein the respective electrical contact pads are electrically coupledwith the respective at least one electronic component of the thirdmodule portions; providing the second wafer with respective electricalcontact pads for each of the second module portions on the secondsurface of the second wafer, wherein the respective electrical contactpads are electrically coupled to the respective metalized via holes ofthe second module portions; and bonding the second wafer onto the thirdwafer such that the second surface of the second wafer is disposed onthe first surface of the third wafer and the respective electricalcontact pads of the third module portions are aligned to the respectiveelectrical contact pads of the second module portions to provide anelectrical connection between the respective electrical contact pads ofthe third module portions and the respective electrical contact pads ofthe second module portions.
 4. The method of claim 1, comprising:providing the first wafer with respective metalized via holes for eachof the first module portions in a material of the first wafer, therespective metalized via holes extending from the first surface of thefirst wafer to the second surface of the first wafer; providing thesecond wafer with respective electrical contact pads for each of thesecond module portions on the first surface of the second wafer suchthat the respective electrical contact pads of the second moduleportions are electrically connected to the respective metalized viaholes of the second module portions; and bonding the first wafer ontothe second wafer such that the respective electrical contact pads of thesecond module portions are electrically connected to the respectivemetalized via holes of the first module portions.
 5. The method of claim3, comprising: providing a fourth wafer being configured for thermalisolation between the third and the second wafer, wherein the fourthwafer comprises metalized via holes in a material of the fourth wafer,wherein the metalized via holes are arranged to electrically couple therespective electrical contact pads of the third module portions to therespective electrical contact pads of the second module portions.
 6. Anoptoelectronic module, comprising: a first substrate comprising a firstmodule portion of the optoelectronic module including at least onepassive optical component; a second substrate comprising a second moduleportion of the optoelectronic module including at least oneoptoelectronic component; a third substrate comprising a third moduleportion of the optoelectronic module, wherein the third module portioncomprises at least one electronic component; wherein the first substratehas a first surface and a second opposite surface, wherein the at leastone passive optical component is arranged on the first surface of thefirst substrate; wherein the at least one passive optical component hasa first and a second side and is configured to modify a beam of lightsuch that a direction of light coupled in the at least one passiveoptical component at the first side is changed and coupled out of the atleast one passive optical component at the second side; wherein thesecond substrate comprises metalized via holes extending in a materialof the second substrate from a first surface of the second substrate toan opposite second surface of the second substrate, wherein the at leastone optoelectronic component is electrically connected to the metalizedvia holes; wherein the second substrate is bonded onto the thirdsubstrate such that the at least one electronic component of the thirdmodule portion is electrically coupled to the at least oneoptoelectronic component of the second module portion by the metalizedvia holes of the second substrate; wherein the first substrate is bondedonto the second substrate such that the first module portion is alignedto the second module portion so that light coupled into the at least oneoptical component of the first module portion at the first side of theat least one optical component is coupled out at the second side of theat least one optical component and is directed to the at least oneoptoelectronic component of the second module portion.
 7. Theoptoelectronic module of claim 6, wherein the third substrate compriseselectrical contact pads of the third module portion, wherein theelectrical contact pads are electrically coupled to the at least oneelectronic component of the third module portion and wherein therespective electrical contact pads are arranged on a first surface ofthe third substrate; wherein the second substrate is bonded onto thethird substrate such that the electrical contact pads of the thirdsubstrate are electrically connected to the metalized via holes of thesecond substrate; wherein the first substrate comprises metalized viaholes extending from a first surface of the first substrate to a secondopposite surface of the first substrate; wherein the second substratecomprises electrical contact pads on the first surface of the secondsubstrate, wherein the electrical contact pads are electricallyconnected to the metalized via holes of the second substrate; andwherein the first substrate is bonded onto the second substrate suchthat the electrical contact pads of the second substrate areelectrically connected to the metalized via holes of the thirdsubstrate.
 8. The optoelectronic module of claim 6, comprising: a fourthsubstrate arranged between the second and the third substrate, whereinthe fourth substrate comprises metalized via holes in a material of thefourth substrate, wherein the metalized via holes are arranged toelectrically couple the respective electrical contact pads of the thirdmodule portion to the respective electrical contact pads of the secondmodule portion.
 9. The optoelectronic module of claim 6, comprising: atleast one fixture being arranged on the first surface of the firstsubstrate to couple at least one optical fiber to the first moduleportion, wherein the at least one fixture is configured to hold the atleast one optical fiber and to align the at least one optical fiber tothe at least one passive optical component such that light is coupledbetween the at least one optical fiber and the at least one passiveoptical component of the first module portion.
 10. A method tomanufacture optoelectronic modules, comprising: providing a first wafercomprising a plurality of first module portions, wherein the first waferhas a first and an opposite second surface; providing a second wafercomprising a plurality of second module portions, wherein the secondwafer has a first and an opposite second surface, wherein each of thesecond module portions comprises at least one optoelectronic component;disposing the first wafer onto the second wafer to provide a wafer stacksuch that the second surface of the first wafer is placed opposite tothe first surface of the second wafer and each of the first moduleportions is aligned to a respective one of the second module portions sothat light coupled in a respective one of the first module portions istransferred to a respective one of the second module portions and isdirected to the respective at least one optoelectronic component of thesecond module portions; and dicing the wafer stack into individualoptoelectronic modules respectively comprising one of the first and thesecond module portions.
 11. The method of claim 10, wherein each of thefirst module portions comprises at least a fixture to hold an opticalfiber; and wherein the at least one fixture is made by a wafer scaleprocess molding directly onto the first wafer and/or using one of asingle wafer with molded elements and several stacked wafers withvarying holes and/or cut outs.
 12. The method of claim 11, comprising:providing at least one of the first and second module portions with atleast one passive optical component; and disposing the first wafer ontothe second wafer to provide a wafer stack such that each of the firstmodule portions is aligned to a respective one of the second moduleportions so that light coupled out of the optical fiber held in therespective at least one fixture of the first module portions is coupledinto the respective at least one passive optical component of one of thefirst and second module portions at the first side of the respective atleast one passive optical component and is coupled out at the secondside of the respective at least one optical component and is directed tothe respective at least one optoelectronic component of the secondmodule portions.
 13. An optoelectronic module, comprising: a firstsubstrate comprising a first module portion, wherein the first substratehas a first and an opposite second surface; a second substratecomprising a second module portion, wherein the second substrate has afirst and an opposite second surface, wherein the second module portioncomprises at least one optoelectronic component; wherein the firstsubstrate is disposed onto the second substrate to provide theoptoelectronic module such that the second surface of the firstsubstrate is placed opposite to the first surface of the secondsubstrate and the first module portion is aligned to the second moduleportion so that light coupled in the first module portion is transferredto the second module portion and is directed to the at least oneoptoelectronic component of the second module portion.
 14. Theoptoelectronic module of claim 13, wherein the first module portioncomprises at least one fixture to hold an optical fiber, wherein the atleast one fixture is disposed on the first surface of the firstsubstrate.
 15. The optoelectronic module of claim 14, wherein at leastone of the first and second module portion is provided with at least onepassive optical component; and wherein the first substrate is disposedon the second substrate to provide the optoelectronic module such thatthe first module portion is aligned to the second module portion so thatlight coupled out of the optical fiber held in the at least one fixtureof the first module portion is coupled into the at least one passiveoptical component of one of the first and second module portions at thefirst side of the at least one passive optical component and is coupledout at the second side of the at least one optical component and isdirected to the at least one optoelectronic component of the secondmodule portion.